INCREASE IN GLOBAL ATMOSPHERIC CONCENTRATIONS OF MERCURY INFERRED FROM MEASUREMENTS OVER THE ATLANTIC-OCEAN

ANTHROPOGENIC processes, such as coal burning, waste incineration and ore refining, are believed to contribute to the emission of mercury into the atmosphere 1-5. The atmospheric concentration of mercury should therefore have increased as a consequence of increases in anthropogenic emissions 3. Indeed, analyses of dated soil 6, peat bog 7,8 and lake-sediment records 8-13 indicate that the deposition of atmospheric mercury may have doubled since the beginning of the nineteenth century. But such an increase in atmospheric mercury concentrations has so far not been detected in ice-core records 14,15 (perhaps because of problems with contamination), and is not consistent with most mercury budgets 2,4,5,16,17, in which natural sources are thought to dominate. Here we present measurements of total gaseous mercury over the Atlantic Ocean for 1977-90, which show that atmospheric concentrations of mercury have in fact increased by 1.46 +/- 0.17% per year in the Northern Hemisphere, and by 1.17 +/- 0.16% per year in the Southern Hemisphere. These rates of increase are consistent with the results of the soil, peat bog and lake-sediment analyses, and lead us to suggest that anthropogenic, rather than natural, sources are at present more important in the mercury cycle.